In literature[1]}: \(\displaystyle \Phi = clip\left( {a/\sqrt{{V_t}}, {\eta _l}\left( t \right), {\eta _u}\left( t \right)} \right)\) , \(\displaystyle {\eta _l}\left( t \right) = \left( {1 - 1/\left( {\left( {1 - {\beta _2}} \right)t + 1} \right)} \right){\alpha ^*}\) , \(\displaystyle {\eta _u}\left( t \right) = \left( {1 + 1/\left( {\left( {1 - {\beta _2}} \right)t} \right)} \right){\alpha ^*}\) .
